A digital signal processor (DSP) is an integrated circuit designed for high-speed data manipulation and used in audio, communications, image manipulation, and other data acquisition and data control applications. (Microsoft Computer Dictionary, 4th ed., Microsoft Press, 1999). Compared to general purpose processors (GPPs), DSPs are optimized for signal processing applications. Specifically, DSPs are typically designed to deal with analog signals, to handle demanding mathematical computations, and to provide substantially real-time response.
For example, most signal processing functions use multiply-and-accumulate operations. A “multiply-and-accumulate” operation is an operation in which two series of numbers are multiplied, and results are summed (e.g., Result:=X1*C1+X2*C2+X3*C3 . . . Xn*Cn). DSPs offer many architectural features, such as a multiply-and-accumulate (MAC) instruction, that actually reduce the number of instructions necessary for efficient signal processing. Thus, DSPs typically perform operations like multiply-and-accumulate much more efficiently than those kinds of operations can be performed by GPPs.
DSPs are used in television receivers, vehicle control systems, cellular telephones, portable music players, digital cameras, telephony infrastructure, and many other kinds of devices. Some applications, particularly those relying on battery power, require DSPs with good power efficiency. For purposes of this disclosure, a DSP with good power efficiency may be referred to as a low power DSP or a low power processor.